Thread created to be a sticky with 3.0 issues and resolutions. Please add info as necessary
Problem with Podcasting Plugin by TSG "Call to a member function add_rewrite_tag() on a non-object"
http://wordpress.org/support/topic/411377
Note plugin author has update.
Problem with HeadSpace2
http://wordpress.org/support/topic/411432
Problem with Event Calendar, see:
http://wordpress.org/support/topic/411422
Problem with WP-Ban, see:
http://wordpress.org/support/topic/418715
Fatal Issue with Allowed memory size exhausted
Use this plugin http://wordpress.org/extend/plugins/memory-bump/ to increase memory allocated to PHP and see http://wordpress.org/support/topic/298403
Stuck in Maintenance Mode:
http://wordpress.org/support/topic/411803
Problem with PHP 5.0.5 (Earthlink hosting) and PHP 4.4:
http://wordpress.org/support/topic/411708?replies=6#post-1578338
